| 摘要 |
PURPOSE:To perform flaw detection over the entire area without any omission by providing plural ultrasonic flaw detectors to a metallic strip which runs lengthwise at intervals, switching the ultrasonic flaw detectors successively at specific intervals of time and transmitting a flaw detection signal, and thus carrying out the flaw detection. CONSTITUTION:The metallic strip 10 is provided with the plural ultrasonic flaw detectors 12a-12c lengthwise at intervals L. An ultrasonic wave signal from an ultrasonic wave transmitter 14 is transmitted to the ultrasonic flaw detectors 12a-12c in order by switching the 1st relay circuit 18 at a specific period based upon the flaw detection area, e.g. at the running speed of the strip 10. The respective ultrasonic flaw detectors 12a-12c performs flaw detection to width l in the width direction of the strip 10 every time a measurement is taken. The flaw detection signal obtained by the flaw detecting operation is received by an ultrasonic wave receiver 16 by switching the 2nd relay circuit 20. Thus, the plural ultrasonic flaw detectors are provided and switched at the period based upon the flaw detection area of the strip to perform the flaw detection, so flaw misdetection is eliminated and the flaw detection is speeded up.
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